Continuous synthetic method and synthetic equipment for 3,4-dichlorotrifluoromethyl benzene

Abstract

The invention discloses a continuous synthetic method and synthetic equipment for 3,4-dichlorotrifluoromethyl benzene. The continuous synthetic method comprises the following steps: using chlorine and p-chlorobenzotrifluoride as raw materials; sufficiently mixing the chlorine and the p-chlorobenzotrifluoride as the raw materials with a circulating material by a raw material mixer; then enabling a mixture to enter a chlorination tower filled with iron filler from the bottom, and carrying out continuous chlorination reaction; using one part of a reactant obtained from the top of the chlorination tower as the circulating material, and enabling the circulating material to return to the raw material mixer for carrying out continuous mixed reaction; refining residual materials to obtain a product 3,4-dichlorotrifluoromethyl benzene. The synthetic equipment comprises a feeding mixer, wherein an outlet of the feeding mixer is communicated with a lower inlet of the chlorination tower; a gas-liquid separator is communicated with a top outlet of the chlorination tower; a liquid phase outlet of the gas-liquid separator is respectively communicated with a product refining device and a liquid phase raw material inlet of the feeding mixer; the iron filler fills the chlorination tower. The continuous synthetic method and the synthetic equipment disclosed by the invention disclosed by the invention can realize continuous production and have the advantages of high capacity, low energy consumption, simplicity and convenience in operation and environment friendliness.

Description

technical field [0001] The invention relates to the technical field of organic synthesis, in particular to a continuous synthesis technology of 3,4-dichlorobenzotrifluoride. Background technique [0002] 3,4 Dichlorotrifluorotoluene is a colorless and transparent liquid with an odor of halogenated benzene, insoluble in water, and miscible with benzene, toluene, ethanol, ether, and halogenated hydrocarbons. The fluorine atom in the molecular structure of 3,4-dichlorotrifluorotoluene makes it have special activity. It is an important pesticide and pharmaceutical intermediate. It can be used as an intermediate for the insecticide fipronil and for the synthesis of diphenyl ether It is an intermediate of fluorine-containing herbicides, and is widely used in fine organic synthesis fields such as medicine, pesticides, and dyes. [0003] The synthesis of 3,4-dichlorobenzotrifluoride can use toluene as a starting material to obtain p-chlorotoluene or 3,4-dichlorotoluene through benz...

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Problems solved by technology

[0007] CN102746108A discloses " the preparation method of 3,4-dichlorobenzotrifluoride ", take p-chlorobenzotrifluoride, chlorine as raw material, take iron powder, iron trichloride as catalyst, carry out chlorination reaction and prepare 3,4- Dichlorobenzotrifluoride, due to the unrestricted source of raw materials, this method is the main preparation method of 3,4-dichlorobenzotrifluoride at present, but this method is also a batch process method, which has the problems of high energy consumption and serious pollution

The batch method uses a tank reactor with mechanical agitation. The residence time of the materials in the reactor is the same, the concentration of the materials in the tank is uniform, and the temperature is easy to control. In the continuous synthesis method, the residence time of the materials in the reactor is not uniform. Very few materials have a long residence time, and the concentration of chlorine gas and high temperature will easily lead to an increase in impurity content

[0012] In summary, the current synthesis of 3,4-dichlorotrifluorotoluene can only use a batch production process, which cannot overcome the technical problems of continuous production, resulting in the continuous production process not being industrialized

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